Parental consent and patient assent forms will be distributed to potential subjects at the University Pediatric and Adolescent Center and the Center for Development Behavior and Genetics. To explain the study, children will be told, "The doctors are doing a study about a disease called autism. If you want to be in this study a small amount of blood will be taken from your arm with a needle. The needle will hurt but will go away after a little while. The doctors will ask you to answer some questions about how you feel. You do not have to be in the study. No one will be mad at you if you don't want to do this."